Esophageal stent

Abstract

A stent comprised of a scaffolding structure having components configured to allow at least a portion of the stent to decrease in diameter in response to an axial force applied to the stent. Further, the components and elements of the stent may be configured to balance transverse forces applied to the stent, thus reducing the incidence of infolding.

The invention claimed is: 
     
       1. An implantable device having a cylindrical shape, configured to be disposed within a body lumen, the device comprising:
 a proximal end, a distal end, and a midsection; 
 a scaffolding of struts, comprising:
 a plurality of annular segments arranged in alignment along a longitudinal direction of the cylindrical shape of the implantable device, each annular segment comprising a plurality of interconnected arms disposed on a circumference of the cylindrical shape of the implantable device, each arm of the plurality of interconnected arms interconnected with a first adjacent arm at an angle to form an apex and interconnected with a second adjacent arm at the angle to form an oppositely directed apex, wherein the plurality of interconnected arms in the proximal end are circumferentially aligned with each other, and the plurality of interconnected arms in the distal end are circumferentially aligned with each other and are offset from the plurality of interconnected arms in the proximal end; 
 a plurality of anti-migration portions each comprising a solid rounded blunt tip, each anti-migration portion coupled to and extending from an apex at a connection of two interconnected arms of the plurality of interconnected arms of the plurality of annular segments of the midsection of the implantable device, wherein each annular segment of the midsection of the implantable device comprises an outside diameter, wherein the two interconnected arms and the solid rounded blunt tip of each given anti-migration portion extend together radially outward relative to the outside diameter of the annular segment of the midsection of the implantable device to which the given anti-migration portion is coupled; 
 a plurality of connectors extending between and interconnecting adjacent annular segments of the plurality of annular segments, the plurality of connectors arranged in an alternating pattern, wherein a given connector of the plurality of connectors that extends in a first longitudinal direction from a given annular segment, of the plurality of annular segments, to a first adjacent annular segment is offset in a circumferential direction of the cylindrical shape from all connectors of the plurality of connectors extending in a second longitudinal direction, opposite the first longitudinal direction, from the given annular segment to a second adjacent annular segment, such that a gap is defined directly in the longitudinal direction to the given connector between the given annular segment and the second adjacent annular segment and between connectors of the plurality of connectors interconnecting the given annular segment and the second adjacent annular segment; and 
 a first plurality of eyelets each coupled to an end annular segment disposed at the proximal end of the implantable device, each eyelet comprising an eyelet body coupled to an end side of, and extending circumferentially from, an apex at a connection of two interconnected arms of the plurality of interconnected arms of the end annular segment, each eyelet body defining an eyelet opening therethrough that is elongated in the circumferential direction of the cylindrical shape such that a maximum length of the eyelet opening is at least twice as long as a maximum width of the eyelet opening; 
 
 a polymeric cover comprising a first layer of silicone, the cover applied to and between the scaffolding of struts, the cover defining an interior region within the scaffolding; and 
 a suture threaded through the eyelet openings of the first plurality of eyelets, 
 wherein at least one set of interconnected arms comprises a straight arm and a curved arm that comprises an inflection point. 
 
     
     
       2. The implantable device of  claim 1 , wherein the angle formed by the interconnection of adjacent arms of an annular segment is 45 degrees. 
     
     
       3. The implantable device of  claim 1 , wherein the scaffolding of struts is comprised of a memory alloy with a thickness of 0.30 mm to 0.6 mm. 
     
     
       4. The implantable device of  claim 3 , wherein the scaffolding of struts comprises an integral frame of nickel-titanium alloy. 
     
     
       5. The implantable device of  claim 1 , further comprising a second plurality of eyelets each coupled to a second end annular segment disposed at the distal end of the implantable device opposite the proximal end, each eyelet of the second plurality of eyelets comprising an eyelet body coupled to an end side of, and extending circumferentially from, an apex at a connection of two interconnected arms of the plurality of interconnected arms of the second end annular segment, each eyelet body defining an eyelet opening therethrough that is elongated in the circumferential direction of the cylindrical shape, the eyelets configured to receive the suture. 
     
     
       6. The implantable device of  claim 1 , wherein strut arms disposed adjacent the proximal and the distal ends are longer than strut arms disposed at the midsection. 
     
     
       7. The implantable device of  claim 6 , wherein connectors disposed adjacent to the proximal and the distal ends are longer than connectors disposed at the midsection. 
     
     
       8. The implantable device of  claim 1 , wherein the polymeric cover further comprises a second layer. 
     
     
       9. The implantable device of  claim 1 , wherein one or more of the connectors comprise a preformed omega shaped portion, wherein a curved member of the omega shaped portion folds back upon legs of the omega shaped portion. 
     
     
       10. The implantable device of  claim 1 , wherein the plurality of annular segments is configured to reduce in diameter in response to an axial force applied to the implantable device. 
     
     
       11. The implantable device of  claim 1 , wherein an inside radius at the angle formed by adjacent arms is from 15 microns to 95 microns. 
     
     
       12. The implantable device of  claim 1 , wherein the device has a longitudinal length from 70 mm to 150 mm. 
     
     
       13. The implantable device of  claim 1 , wherein the device has a diameter of 12 mm to 25 mm. 
     
     
       14. An implantable device having a cylindrical shape, configured to be disposed within a body lumen, the device comprising:
 a scaffolding of struts, comprising:
 a plurality of annular segments arranged in alignment along a longitudinal direction of the cylindrical shape of the implantable device, each annular segment comprising a plurality of interconnected arms disposed on a circumference of the cylindrical shape of the implantable device, each arm of the plurality of interconnected arms interconnected with a first adjacent arm at an angle from 30 degrees to 60 degrees to form an apex and interconnected with a second adjacent arm at the angle to form an opposing apex, wherein the plurality of interconnected arms in a proximal end of the implantable device are circumferentially aligned with each other, and the plurality of interconnected arms in a distal end of the implantable device are circumferentially aligned with each other and are offset from the plurality of interconnected arms in the proximal end; 
 a plurality of anti-migration portions each comprising a solid rounded blunt tip, the solid rounded blunt tip portion lacking an opening, each anti-migration portion coupled to and extending from an apex at a connection of two interconnected arms of the plurality of interconnected arms of the plurality of annular segments, wherein each annular segment comprises an outside diameter, wherein the two interconnected arms and the solid rounded blunt tip of each given anti-migration portion extend together radially outward from the outside diameter of the annular segment to which the given anti-migration portion is coupled; 
 a plurality of connectors extending between and interconnecting adjacent annular segments of the plurality of annular segments, the plurality of connectors arranged in an alternating pattern, wherein a given connector of the plurality of connectors that extends in a first longitudinal direction from a given annular segment to a first adjacent annular segment is offset in a circumferential direction of the cylindrical shape from all connectors of the plurality of connectors extending in a second longitudinal direction, opposite the first longitudinal direction, from the given annular segment to a second adjacent annular segment such that, for each annular segment, all connectors extending in the first longitudinal direction are offset in the circumferential direction of the cylindrical shape from all connectors on the same annular segment that extend in the second longitudinal direction; 
 a first plurality of eyelets each coupled to a first end annular segment disposed at a first longitudinal end of the cylindrical shape, each eyelet comprising an eyelet body coupled to an end side of, and extending circumferentially from, an apex at a connection of two interconnected arms of the plurality of interconnected arms of the first end annular segment, each eyelet body defining an eyelet opening therethrough that is elongated in the circumferential direction of the cylindrical shape such that a major axis of the eyelet opening is longer than a minor axis of the eyelet opening; and 
 a second plurality of eyelets each coupled to a second end annular segment disposed at a second longitudinal end of the cylindrical shape opposite the first longitudinal end, each eyelet comprising an eyelet body coupled to an end side of, and extending circumferentially from, an apex at a connection of two interconnected arms of the plurality of interconnected arms of the second end annular segment, each eyelet body defining an eyelet opening therethrough that is elongated in the circumferential direction of the cylindrical shape such that a major axis of the eyelet opening is longer than a minor axis of the eyelet opening; 
 
 a first suture threaded through the eyelet openings of the first plurality of eyelets; 
 a second suture threaded through the eyelet openings of the second plurality of eyelets; and 
 a cover coupled to the scaffolding of struts, the cover comprising a silicone layer, 
 wherein one or more of the plurality of annular segments is configured to reduce in diameter in response to an axial force applied to the implantable device, 
 wherein one or more of the connectors comprise a preformed omega shaped portion, wherein a curved member of the omega shaped portion folds back upon legs of the omega shaped portion, and 
 wherein at least one set of interconnected arms comprises a straight arm and a curved arm that comprises an inflection point. 
 
     
     
       15. The implantable device of  claim 14 , wherein the scaffolding of struts is comprised of a memory alloy. 
     
     
       16. The implantable device of  claim 15 , wherein the scaffolding of struts has a thickness of from 0.30 mm to 0.60 mm. 
     
     
       17. The implantable device of  claim 14 , wherein an inside radius of the angle formed by adjacent arms is from 15 microns to 95 microns. 
     
     
       18. The implantable device of  claim 14 , wherein the cover further comprises a second layer. 
     
     
       19. A method of treating a stricture or fistula in a body lumen comprising:
 obtaining the implantable device of  claim 1 ; and 
 deploying the implantable device within an esophagus of a patient. 
 
     
     
       20. The method of  claim 19 , further comprising decreasing the diameter of the plurality of annular segments of the implantable device by applying an axial force to the implantable device.